Field of the Invention
The present invention relates to an image capture apparatus and a control method thereof.
Description of the Related Art
Since depth of field is determined by a combination of various factors such as subject distance, aperture value, angle of view (focal length) and image sensor size, capturing an image in which a desired area on the screen is within the depth of field takes knowledge and experience, and is not easy. Japanese Patent Laid-Open No. 2009-88742 discloses an image capture apparatus which generates a single image by capturing the same scene a plurality of times while changing the focus distance, depth of field or the like, and extracting and combining the areas that are in focus within the obtained images. This image capture apparatus enables an image focused on a plurality of subjects at different distances to be obtained after image capture. Also, LIANG, Chia-Kai, et al., “Programmable Aperture Photography: Multiplexed Light Field Acquisition” (ACM Transactions on Graphics (TOG), Vol. 27, No. 3, ACM, 2008) describes an image capture apparatus in which a microlens array is arranged in front of the image sensor, and an image capture apparatus that performs image capture with different positions of the opening of the aperture. Based on the images captured with this image capture apparatus, the focus distance, depth of field or the like of an image can be changed after image capture, using light field photography.
With the image capture apparatus disclosed in Japanese Patent Laid-Open No. 2009-88742, image capture needs to be performed for various combinations of focusing lens position (focus position), aperture value or the like. In this case, the interval between focusing lens positions increases when the number of combinations is small, and an image focused on the desired subject may not be obtained. Also, when the number of combinations is large, the number of times image capture is performed increases, thus increasing the chances of the subject moving during the image capture period, and making it difficult to obtain a natural-looking combined image. Also, since images that are not be focused on any subject will be captured, efficiency is compromised.
Also, with the image capture apparatus described in Liang, Chia-Kai, et al., the pixel count of the image data that is obtained is much lower than the pixel count of the image sensor, due to a configuration that generates each pixel of the final image from a plurality of pixel values of the captured image. Also, since image generation requires complex computations, there is a slowing of response.